We are in the gradual process of developing a Picture Archiving and Communications System (PACS) for our Radiology Department. At the present time, we have completed construction of the first component for that system; the component is a viewing station that we term the Arizona Viewing Console or AVC. We have begun characterization of this viewing console and have performed usage studies. As a result of our experiences with this console, we have concluded that certain of its performance specifications should be changed. This research proposal is directed toward implementing those changes and measuring their effects. The proposal is divided into five tasks: (1) modify the Arizona Viewing Console, (2) construct a high performance viewing console, (3) provide an image control software environment, (4) refine our display characterization facilities and (5) evaluate console performance and acceptance by radiologists. The modifications to the AVC are for attaining increased speed of access to the images by expanding the semiconductor memory of the system and to allow more flexible software to be implemented. The modifications are to be tested and then integrated into the design of the high performance console. We will produce a machine independent software environment for handling images n the PACS; one element of this environment will be providing images to the display console. This environment will make possible efficient evaluation of the display console when functioning as a part of the PACS system. It will also strongly reduce the amount of effort which must be invested in implementing changes and adding new functions. Characterizing and evaluating the display as part of a more complicated system is an extension of work in our ongoing research. The characterization consists of physical, psychophysical and clinical evaluation. We will be adding capabilities to a cart we have designed and constructed for in-place measurement of CRT characteristics. The most fundamental important change will be the additional CCD camera-based sensors to the present photomultiplier. In addition to physical measurement techniques, we will apply psychophysical methods to judging the effectiveness and acceptability of the various configurations of the viewing consoles. These system evaluations will be extended to evaluations where we will use a fiber-optic network connection to image acquisition modalities for comparisons to film-based diagnosis.